Questions and Answers of The Nature Properties of Soils

What differences would you expect in nitrate contents of streams from a forested watershed and one where agricultural crops are grown, and why?
Why do CAFOs (concentrated animal-feeding operations) on industrial-style farms present some environmental and health problems relating to nitrogen? What are these problems and how can they be
About 2000 kg of wheat straw was applied to 1 ha of land. Tests showed the soil to contain 25 kg nitrate-N per ha. The straw contained OA% N. Now much N was applied in the straw? Explain why two
Both sulfur and nitrogen are added to soils by atmospheric deposition. In what situations is this phenomenon beneficial and under what circumstances is it detrimental?
A sandy loam soil under a golf course fairway has an organic matter content of 3% by weight. Calculate the approximate amount of nitrogen (n kg N/ha) you would expect this soil to provide for plant
The manager of a landscaping company is having a bit of an argument with the landscape architect about plans to fertilize and lime the soil in a new installation before planting turf and ornamental
The manager of a landscaping company is having a bit of an argument with the landscape architect about plans to fertilize and lime the soil in a new installation before planting turf and ornamental
Explain why compost is more environmentally sustainable than peat for use in potting media and as an amendment for golf course greens.
In what ways are soils involved in the greenhouse effect that is warming up the Earth? What are some common soil-management practices that could be changed to reduce the negative effects and increase
What are the advantages of using gypsum (CaSO4 • 2H2O) in the reclamation of a sodic soil? Show the chemical reactions that take place.
Using the information in Table and assuming only Na+ and Ca2+ are present and the SAR = 1, calculate the TDS (mg/L) and ECw, of the solution represented by 10 mmolc L-1 on the x-axis scale in Figure.
The ill effects of acidity in subsoils can be ameliorated by adding gypsum (CaSO4 • 2H2O) to the soil surface. What are the mechanisms responsible for this effect of the gypsum?
Vital is acid rain and why does it seem to have greater impact on forests than on commercial agriculture'
Calculate the amount of pure CaCO3 that could theoretically neutralize the H+ ions in a year's worth of acid rain if a 1-ha site received 500 mm of rain per year and the average pH of the rain was
Discuss the significance of soil pH in determining specific nutrient availabilities and toxicities, as well as species composition of natural vegetation in an area.
How much limestone with a CaCO3 equivalent of 90% would you need to apply to eliminate exchangeable aluminum in an Ultisol with CEC = 8 cmolc/kg and an aluminum saturation of 60%?
Based on the buffer pH of your soil sample, a lab recommends that you apply 2 Mg of CaCO3 equivalent to your field and plow it in 18 cm deep to achieve your target pH of 6.5. You actually plan to use
A landscape contractor purchased 10 dump-truck loads of "topsoil" excavated from a black, rich appearing soil in a coastal wetland. Samples of the soil were in immediately sent to a lab to be sure
A neighbor complained when his azaleas were adversely affected by a generous application of limestone to the lawn immediately surrounding the azaleas. To what do you ascribe this difficulty? How
What are the primary sources of alkalinity in soils? Explain.
Compare the availability of the following essential elements in alkaline soils with that in acid soils:(1) iron,(2) nitrogen.(3) molybdenum. And(4) phosphorus.
The iron analysis of an arid-region soil showed an abundance of this element, yet a peach crop growing on the soil showed serious iron deficiency symptoms. What is a likely explanation?
A soil with an abundance of CaCO3 may have a pH no higher than about 8.3, while a nearby soil with high Na2CO3 content has a pH of 10.5. What is the primary reason for this difference?
An arid-region soil. when it was first cleared for cropping, had a pH of about 8.0. After several years of irrigation. the crop yield began to decline. the soil aggregation tended to break down, and
What physical and chemical treatments would you suggest to bring the soil described in question 5 back to its original state of productivity?
What are some of the adverse consequences of using wetlands as recipients of irrigation wastewater?
Calculate the leaching requirement to prevent the buildup of salts in the upper 45 cm of a soil if the ECdw of the drainage water is 6 dS/m and the ECiw, of the irrigation water is 1.2 dS/m.
Calculate the quantity of gypsum needed to reclaim a sodic soil (EPS = 30%) when CEC = 25 cmolc/kg and pH is 10.2. Assume you want ESP no higher than 4%.
What is functional redundancy, and how does it help soil ecosystems continue to function in the face of environmental shocks such as fire, clear-cutting, or tillage?
What is functional redundancy, and how does it help soil ecosystems continue to function in the face of environmental shocks such as fire, clear-cutting, or tillage?
In the example illustrated in Table. identify the organisms. if any, that play the roles of primary producers. pdmay consumers, and secondary oansumers. and tertiary consumers.
Describe some of the ways in which mesofauna play significant roles in soil metabolism even though their biomass and respiratory activity is only a small fraction of the total in the soil.
What are the four main types of metabolism carried out by soil organisms relative to their sources of energy and carbon?
What role does O2 play in aerobic metabolism? What elements take its place under anaerobic conditions?
A mycorrhiza is said to be a symbiotic association. a) What are the two parties in this symbiosis, b) What are the benefits derived by each party (why is this mutually beneficial)?
In what ways is soil improved as a result of earthworm activity? Are there possible detrimental effects as well?
What is the rhizosphere. and in what ways does the soil in the rhizosphere differ from the rest of the soil?
Explain and compare the effects of tillage and manure application on the abundance diversity of soil organisms.
What is induced systemic resistance, and how does it work?
What is a disease-suppressive soil? Explain the difference between general and specific forms of suppression.
Discuss the value and limitations of using specific inoculants for (a) mycorrhizae and (b) disease suppression_ For each type of inoculation, describe a situation for which the chances would be very
What are the main food web roles played by nematodes, and how can we visually (with a microscope) distinguish among nematodes that play these roles?
In what ways are actinomycetes like other groups of bacteria, and in what ways are they special?
Explain with two soil examples the concept of an ecosystem engineer.
Compare the amounts of carbon in Earth's standing vegetation, soils, and atmosphere.
If you wanted to apply an organic material that would make a long-lasting munch on the soil surface, you would choose an organic material with what chemical and physical characteristics?
Descibe how the addition of certain types of organic materials to soil can cause a nitrate depression period. What are the ramifications of this phenomenon for plant growth?
In addition to humic substances. what other categories of organic materials are found in soils?
Some scientists include plant litter (surface residues) in their definition of soil organic matter, while others do not. Write two brief paragraphs, one justifying the inclusion of litter as soil
What soil properties are mainly influenced by the active and passive pools, respectively, of organic matter?
In this book and elsewhere, the terms soil organic matter are used to mean almost the same thing. How are these terms related, conceptually and quantitatively? Why is the term organic carbon
Explain, in terms of the balance between gains and losses, why cultivated soils generally contain much lower levels of organic carbon than similar soils under natural vegetation.
Draw a simple diagram of the hydrologic cycle using a separate arrow to represent these processes: evaporation, transpiration, infiltration, interception, percolation, surface runoff, and soil
Describe and give an example of the indirect effects of plants on the hydrologic balance through their effects on the soil.
State the basic principle that governs how water moves through the SPAC. Give two examples, one at the soil-root interface and one at the leaf-atmosphere interface.
Define potential evapotranspiration and explain its significance to water management.
What is the role of evaporation from the soil (E) in determining water-use efficiency, and how does it affect ET? List three practices that can be used to control losses by E.
Weed control should reduce water losses by what process?
Comment on the relative advantages and disadvantages of organic versus plastic mulches.
What does conservation tillage conserve? How does it do it?
Explain under what circumstances earthworm channels might increase downward saturated water flow. but not have much effect on the leaching of soluble chemicals applied to the soil.
What will be the effect of placing a perforated drainage pipe in the capillary fringe zone just above the water table in a wet soil? Explain in terms of water potentials.
What soil features may limit the use of a site for a septic tank drain field?
Which irrigation systems are likely to be used where: (a) water is expensive and the market value of crops produced per hectare is high, and (b) the cost of irrigation water is subsidized and the
What are the two principal gases involved with soil aeration, and how do their relative amounts change as one samples deeper into a soil profile?
What is aerenchyma tissue. and how does it affect plant—soil relationships?
If the redox potential for a soil at pH 6 is near zero, write two reactions that you would expect to take place. How would the presence of a great deal of nitrate compounds affect the occurrence of
It is sometimes said that organisms in anaerobic environments will use the combined oxygen in nitrate or sulfate instead of the oxygen in O2. Why is this statement incorrect? What actually happens
If an alluvial forest soil were flooded for 10 days and you sampled the gases evolving from the, wet soil, what gases would you expect to find (other than oxygen and carbon dioxide)? In what order of
Explain why warm weather during periods of saturation is required in order to form a hydric soil.
If you were in the field trying to delineate the so-called drier end of a wetland area, what are three soil properties and three other indicators that you might look for?
For each Of these gases, write a sentence to explain its relationship to wetland conditions: ethylene, methane, nitrous oxide, oxygen, and hydrogen sulfide.
What are the three major components that define a wetland?
Discuss four plant processes that are influenced by soil temperature.
Explain how a brush fire might lead to subsequent mudslides, as often occurs in California.
If you were to build a house below ground in order to save heating and cooling costs, would you firmly compact the soil around the house? Explain your answer.
If you measured a daily maximum air temperature of 28 °C at 1 P.M., what might you expect the daily maximum temperature to be at a 15-cm depth in the soil? At about what time of day would the
In relation to soil temperature, explain why conservation tillage has been more popular in Missouri than in Minnesota.
Describe the soil colloidal complex, indicate its various components. and explain how it tends to serve a tank" for plant nutrients.
Describe the soil colloidal complex, indicate its various components. and explain how it tends to serve a tank" for plant nutrients.
How do you account for the difference in surface area associated with a grain of kaolinite clay compared to that of montmorillonite, a smectite?
Contrast the difference in crystalline structure among kaolinite, smectites, fine-grained micas, vermiculites and chlorites.
There are two basic processes by which silicate clays are formed by weathering of primary minerals. Which of these would likely be responsible for the formation of (1) fine-grained mica, and (2)
If you wanted to find a soil high in kaolinite, where would you go? The same for(1) Smectite and(2) Vermiculite?
Which of the silicate clay minerals would be most and least desired if one were interested in(1) A good foundation for a building,(2) A high cation exchange capacity,(3) An adequate source of
Which of the following would you expect to be most and least sticky and plastic when wet:(1) a soil with significant sodium saturation in a semiarid area.(2) a soil high in exchangeable calcium in a
A soil contains 4% humus, 10% montmorillonite, 10% vermiculite, and 10% Fe, Al oxides. What is its approximate cation exchange capacity?
Calculate the number of grams of Al3+ ions needed to replace 10 mot of Ca2+ ion from the exchange complex of 1 Kg of soil.
A soil has been determined to contain the exchangeable cations in these amounts: Ca2+ = 9 emote. Mg2+ = 3 cmok. K+ = 1 emote. Al3+ = 3 cmolc.(a) What is the CEC of this soil?(b) What is the aluminum
A 100 g sample of a soil has been determined to contain the exchangeable cations in these amounts: Ca2+ = 90 mg, Mg2+ = 35 mg, K+ = 28 mg, Al3+ = 60 mg.(a) what is the CEC of this soil?(b) What is
A 100 g sample of a soil was shaken with a strong solution of BaCl2 buffered at pH 8.2. The soil suspension was then filtered, the filtrate was discarded, and the soil was thoroughly leached with
Explain the importance of Kd and Koc in assessing the potential pollution of drainage water. Which of these expressions is likely to be most consistently characteristic of the organic compounds in
What is meant by buffering? Why is it so important in soils, and what are the mechanisms by which it occurs?
An accident at a nuclear power plant has contaminated soil with strontium -90 (Sr2+). a dangerous radionuclide. Health officials order forages growing in the area to be cut baled. and destroyed.
Explain why there is environmental concern about the adsorption by soil colloids of such normally beneficial substances as antibiotic drugs and natural insecticides.
Soil pH gives a measure of the concentration of H+ ions in the soil solution. What if anything, does it tell you about the concentration of OH- ions? Explain.
Describe the role of aluminum and its associated ions in soil acidity. Identify the ionic species involved and the effect of these species on the CEC of soils.
If you could somehow extract the soil solution from the upper 16 cm of 1 ha of moist acid soil (pH = 5), how many kg of pure CaCO3 would be needed to neutralize the soil solution (bring its pH to
If you were investigating a site for a proposed housing development, how could you use soil colors to help predict where problems might be encountered?
You are considering the purchase of some farm land in a region with variable soil textures. The soils on one farm are mostly sandy loams and loamy sands. while those on a second farm are mostly day

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